Method of manufacturing bodies consisting of helically wound wire



Feb. 25, 1964 J. J. F. DIETZ METHQD OF MANUFACTURING BODIES CONSISTINGOF HELICALLY WOUND WIRE Filed Oct. '19, 1959 FIG; 2

FIG.1

R o T N E v m ohunnzs Jcrcobus franciscus dictz AGENT United StatesPatent 3,122,176 lvlETHOD OF MANUFACTURING BQDIES CJl SISTING 0FHELICALLY WOUND WIRE Johannes .lacobns Fran-ciscus Dietz, Eindhoven,Netherlands, assignor to North American Philips (Jompany,

lilo, New York, N.Y., a corporation of Bciaware Filed Oct. 19, 1959,Ser. No. 347,311 Qlaims priority, application Netherlands Oct. 27, 19582 Claims. (Ci. 14tl71.5)

This invention relates to a method of, and a device for, manufacturingbodies consisting of helically wound wire, in particular filaments forthermionic valves, electric incandescent lamps and the like, in which awire is coiled on a mandrel and the obtained product is passed through aheating zone.

in some lamps and valves, these bodies are shaped into a form havingcomparatively sharp curves, for example the form of an M. The bodiesshow a tendency to become distorted or even to be twisted together, andthis must be prevented. Hitherto, for this purpose a method has beenemployed comprising the steps of passing a wire coil d on a mandrelthrough a furnace, cutting the Wire and mandrel into lengths, arrangingthese lengths in boats in straightened condition and subsequentlyheat-treating them again so that the strains produced in the process ofwinding into helices (which process is also referred to as coilingprocess), which strains are significant in the said undesirabledistortion, are relieved. Subsequently the bodies can be shaped by meansof a bending machine and be further worked, for example becataphoretically coated with a paste and sintered.

This sequence of operations requires much manual labor. Mechanization issubstantially impossible.

The present invention provides a method which enables mechan zation tobe effected by suitable means.

According to the invention, during the heat treatment the mandrel istwisted in a direction such that the wire coiled on it is slightlyloosened.

In one embodiment of the method in accordance with the invention, therate of twisting is matched to the speed of passage through the heatingzone.

it has been found that the use of the invention enables a wire to beobtain d which is coiled on a spool and can be cut and bentautomatically, after which it can be transported automatically tofurther operational stations, so that the entire process can bemechanized. The distortion and the twisting together of the bent wirereferred to hereinbefore can be entirely prevented.

in addition, the risk of fracture of the wire at the bending points, forexample the tips of the M, is reduced in that the wire is coiled moreloosely on the core.

A device for c rrying out the method in accordance with the invention isprovided in known manner with a take-oi spool for wl'e coiled on amandrel, a take-up spool for tms mandrel and wire, and at least onefurnace through which the wire passes on its way from the take-off spoolto the take-up spool.

According to the invention, one of the spools is rotatable about an sothat the wire and the mandrel can be twisted on their way between thespools.

In order that the invention may be readily carried into effect, it willnow be described in detail, by way of example, with reference to theaccompanying diagrammatic drawings in which,

FIGURE 1 is a front elevation of an embodiment of a device in accordancewith the invention, and

FIGURE 2 is a side elevation thereof, while FIGURE 3 is an elevation ofa filament bent into the form of an M, and

FIGURE 4 is an elevation of a distorted M-shaped filament.

In FZGURES 1 and 2, a take-off spool 1 is mounted for rotation on aspindle 2 which is secured to an arm 3 which, at its lower end, carriesa guiding roller 4 for a wire 5 helically wound on a core, while to itsupper end there is attached a disc 6 which is secured to a shaft 7 whichis mounted for rotation in a bearing 7a.

The shaft 7 is driven, through a transmission comprising pulleys 8 and 9and a cord 10, but a shaft 11, and this is again driven, through atransmission 12, 13, 14, by a motor 15.

The wire 5 comes ofi the spool 1 and passes over roller 4 through twofurnaces 16 and 17 to a take-up spool 19 mounted for rotation on aspindle 13. The frame of the machine is designated 20.

he desired torsion of the filament between the two spools is determinedby the number of revolutions of the spool 1 about the shaft 7.

It has been found that for a wire of approximately 50/, diameter, whichis coiled with a pitch of about /,u on a mandrel of approximately 70/,udiameter, a rate of passage through the furnaces 16 and 17 of 330 cms,per minute and a speed of the spool 1 about the shaft of about 700revolutions per minute substantially prevent the distortion and thetwisting together of the coiled wire at the bending points A and B(FIGURE 4) of an M-shaped filament.

This is onl an example. The twisting speed may be increased, in whichevent the rate of passage through the f rnace must also be increased.

What is claimed is:

i. A method of manufacturing helical wire coiled on a mandrel comprisingwinding said mandrel with said helical wire thereon on a take-0t spool,passing said combined mandrel and wire through a heating zone at a speedof 330 cms. per minute and thence on a take-up spool, twisting said wirebetween said take-oil and take-up spoois in a manner such that the wirecoiled on said mandrel is slightly loosened, said combined mandrel andwire being twisted at a rate which is matched to the rate of passagethrough the heating zone at about 650 to 750 revolutions per minute andin such a direction that the wire coiled thereon is slightly loosened,said wire being about 50,11. in diameter coiled on a mandrel of approxi-7'iln diameter and with a pitch of approximately 2. A device formanufacturing helical wire of about 56 in diameter and a pitch of about80a coiled on a mandrel of a, proximately 70 1 in diameter comprising atal1e-up spool and a take-off spool, said take-up spool and take-offspool being mounted for rotation, said helical Wire being delivered fromsaid take-oft spool to said take-up spool, at least one furnace throughwhich said wire is passed at a speed of approximately 330 cm. per minuteon its way from the take-off spool to said take-up spool, one of saidspools being rotated about an axis at about 650 to 750 revolutions perminute in a manner such that the wire together with the mandrel can betwisted on its way between the spools.

References Cited in the file of this patent UNITED STATES PATENTS

1. A METHOD OF MANUFACTURING HELICAL WIRE COILED ON A MANDREL COMPRISINGWINDING SAID MANDREL WITH SAID HELICAL WIRE THEREON ON A TAKE-OFF SPOOL,PASSING SAID COMBINED MANDREL AND WIRE THROUGH A HEATING ZONE AT A SPEEDOF 330 CMS. PER MINUTE AND THENCE ON A TAKE-UP SPOOL, TWISTING SAID WIREBETWEEN SAID TAKE-OFF AND TAKE-UP SPOOLS IN A MANNER SUCH THAT THE WIRECOILED ON SAID MANDREL IS SLIGHTLY LOOSENED, SAID COMBINED MANDREL ANDWIRE BEING TWISTED AT A RATE WHICH IS MATCHED TO THE RATE OF PASSAGETHROUGH THE HEATING ZONE AT ABOUT 650 TO 750 REVOLUTIONS PER MINUTE ANDIN SUCH A DIRECTION THAT THE WIRE COILED THEREON IS SLIGHTLY LOOSENED,SAID WIRE BEING ABOUT 50U IN DIAMETER COILED ON A MANDREL OFAPPROXIMATELY 70U IN DIAMETER AND WITH A PITCH OF APPROXIMATELY 80U.